How disgust protects us from infections

Disgust

Disgust has a repellent effect that prompts one not to consume the food that causes this sensation. But it’s not just a question of flavor: this reaction would protect us from the risk of infection by germs transmitted through food or drink.

We all know this. Meat that smells bad, food that looks suspicious, a drink with questionable taste: the immediate reaction is disgust, and we move on. In our Western societies, where abundance is the rule and where food meets increasingly strict health standards, these situations most often occur when the consumer has not respected certain hygiene rules, in particular the storage conditions (cold chain, deadline, etc.). In less developed, less wealthy societies, it is different: we do not always have a choice.

Tradition and modernity

In human evolution, disgust would correspond to an emotion whose function is to encourage the avoidance of foods liable to transmit infectious germs, whether they are viruses, bacteria or parasites. And this emotion is not frozen: it is dependent on how living conditions change.

For the first time, this hypothesis was tested in real conditions by an American team (University of Colorado). The study was conducted with three Shuar communities (formerly the Jivaros) residing in Ecuador. This population is of major interest in the context of this study, since in some families, the way of life has remained traditional, particularly in terms of food production and consumption, while in others, “modernity” has gained ground with the introduction of industrial food products, the connection to water and electricity, and the purchase of household appliances such as a refrigerator or a stove.

A good or a bad thing?

The researchers found that the further a person departs from the traditional way of life, the more their susceptibility to food disgust increases. This is explained by the diversification of food sources, with access to foods that are apparently “more” microbiologically “safe”, and therefore the possibility of rejecting those that appear suspect. In terms of health, there is a very clear consequence, since this increased feeling of disgust is associated with a lower rate of foodborne infections.

Is the progression of this “modernity” a good or a bad thing? In this case, the question is posed differently, and it refers to a complex and multidirectional relationship between disgust, infections and variations in the environment. What is established is that this association is scalable, and that it takes place in a cost – benefit context.

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